After the update from 0.52 to 0.53 I get an error message on my blog (line 2xxx).

WordPress: 3.4.1

I have deactivate the plugin. When I activate it again I get the message:
Fatal error: Can't use function return value in write context in /home/www/cwcity/hosting/m/r/mrcool/htdocs/grg/wp-content/plugins/widget-logic/widget_logic.php on line 264

Remember you can forcefully deactivate the plugin by deleting it from /wp-content/plugins/widget-logic. Deleting the plugin files will not delete its settings.

After deletion, re-install the plugin. Do not reactivate it until the developer releases version 0.54. Point of re-installing it is that you'll know when the new release is out because WP will tell you.